1. Field of the Invention
The present invention relates generally to liquid flow meters, and more specifically, to a positive flow meter for incorporation within an electrically operable valve assembly for controlling a water supply.
2. Background of the Invention
Water supply control systems for household use generally require a measure of water flow, so that water leaks may be detected. Typical flow meters use a paddle or other device inserted into the liquid flow. Displacement of the paddle against a restoring force provides a linear or angular measurement of the flow amount. However, paddle type flow meters generally cannot measure the low flow rates associated with slow water leaks.
A water supply control system also generally requires an electrically operable valve to control water flow and other devices such as a pressure regulator and backflow preventor. The combination of all of these devices along with a flow meter makes a very large in-line installation in a typical water supply control system and requires a number of connections, each that may be susceptible to failure. Assembly time is also increased when the devices used are discretely installed in-line.
Therefore, it would be desirable to provide a flow meter for measuring low flow rates associated with small leaks. It would further be desirable to provide a flow meter that may be integrated with other devices such as electrically controllable valves, backflow preventors and pressure regulators, whereby fewer interconnects, smaller in-line installation space and less assembly time is required.
The above objective of providing a flow meter for measuring low flow rates that does not require additional in-line space, additional interconnects and assembly time is achieved in a positive flow meter that may be constructed integral to an electrically controllable valve, pressure regulator and backflow preventor. The water system control device and flow meter are thus incorporated within one housing.
The positive flow meter is integrated in a water control system valve or backflow preventor that include a main chamber and a bypass channel. A movable indicator is disposed within the bypass channel and a position sensor is located near the bypass channel so that the position of the movable indicator is detectable via the sensor. The flow meter may further be integrated with a backflow preventor having a flow resisting element and a position sensor located near the flow resisting element so that a position of the flow resisting element may be detected to provide a measure of flow in the forward direction. A combination of sensors may be used on the flow resisting element and the bypass channel indicator to provide a high flow/low flow indication.
The foregoing and other objectives, features, and advantages of the invention will be apparent from the following, more particular, description of the preferred embodiment of the invention, as illustrated in the accompanying drawings.